Planetary Radio: Space Exploration, Astronomy and Science - New Horizons at Jupiter: A Report From Alan Stern

Episode Date: May 28, 2007

New Horizons at Jupiter: A Report From Alan SternLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

New Horizons P.I. Alan Stern on the Jupiter flyby, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. Yes, Alan Stern remains the principal investigator for the New Horizons mission to Pluto and beyond. In spite of the other little job he recently picked up, that would be associate administrator of NASA's science mission directorate, making him a very, very busy guy. So we figured when we got the chance to talk with him again, we should grab it.

That chance came just a few days ago. This means we're going to delay our coverage of the Lunar Regolith Challenge till next week. Later today, we'll drop in on our pal Bruce Betts for a look at the crowded night sky, a particularly fun random space fact, and the latest installment of our weekly space trivia contest, which has won a Planetary Radio t-shirt for one of you. And then there's the news, including a new find by Spirit, one of the Mars Exploration rovers.

Well, what did you think, that they were just sitting around collecting dust up there? Well, yeah, they do that too, but Spirit has discovered that some of that dust, and soil and rock, is about 90% silica. The find was made in a little patch that the rover has been working close to for six months. Now, as far as we know, the only way to create a deposit of silica like that involves a lot of water. It's among the best evidence so far that some of the surface of the red planet was once soaking wet. And what might have been living in that water? Wouldn't we all like to know? Get the details at planetary.org. Speaking of dust, over on the other side of Mars, Spirit's sister, Opportunity, has a new lease on

life thanks to three more of what are called dust cleaning events. Think gone with the wind. Electricity production by the rover's solar cells is now at a level not seen since it arrived well over three years ago. You'll find this story in Emily Lakdawalla's blog at planetary.org, where she also explains why scientists are excited about a black hole on Mars. No, not that kind of black hole, the kind that may have revealed a large cave. Okay, who caught my stupid mistake last week? Magellan was a terrific spacecraft that told us a lot about Venus, but it did not then move on to Mercury.

That would be the messenger probe. How does spacecraft find their way through the vacuum, and how do we know where they are in the first place? Those are the questions Emily Lakdawalla will cover in this week's Q&A. I'll be right back with Alan Stern of the New Horizons Mission. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, how do we navigate the solar system? What's the spatial reference? Is it the sun?

Celestial navigation is one of the many challenges to planetary exploration. Absolutely everything in the solar system is moving, even the sun. So there's really no reference frame that can be fixed to a single non-moving location. The coordinate system that's used most frequently is an XYZ system known as J2000, where the XY plane is the average plane of Earth's equator and the X axis points in the direction of the vernal equinox as of January 1, 2000. That's in the direction of the constellation Aries. When spacecraft are cruising from one planet to another,

the center of this coordinate system is most often chosen to be the center of mass of the solar system. This isn't the same as the center of the sun. Other massive bodies in the solar system, most notably Jupiter, tug the sun around so that it moves with respect to the solar system's center of mass. All those other massive bodies also tug spacecraft around, which means that navigators have to know the positions and masses of every large body that's anywhere near a spacecraft to a high accuracy.

So how do the navigators know what a spaceship's coordinates are? Stay tuned to Planetary Radio to find out. Stay tuned to Planetary Radio to find out. New Horizons needed Jupiter to redirect it to Pluto and give it a sizable boost in velocity. But the Jovian system of planet, moons, and rings also offered a great opportunity to rehearse the spacecraft's 2015 task. Principal Investigator Alan Stern and his team took full advantage. On February 27, the probe passed just 1.4 million miles from Jupiter. It essentially worked flawlessly,

gathering images and data that even the Galileo orbiter could not. That data is wowing scientists, including Alan himself. I found him in his office at NASA headquarters last week, where he now serves as associate administrator of the Science Mission Directorate. Alan, welcome back to Planetary Radio. Hey, Matt. It is so good to get you, and I know you've already warned me there may be some interruptions there. It's this other job that you've picked up. You know, I don't know, wasn't Pluto enough? Well, I thought in addition to a day job that wasn't enough, so maybe I'd just take a night job and work the whole 24. All right. Well, before they interrupt you, tell us, have you now received all of the data that we're going to be picking up from that Jupiter encounter? No, we're past the 90

percent point on the close approach data. We still have just a few items left up on the spacecraft. In addition, we're still flying down Jupiter's magnetotail, and that data is not even collected. We get data every week, but we'll be doing this through the end of June. The data that you've gotten so far, though, first of all, do you have an idea how much that is in gigabytes or whatever? Yeah, we quote gigabits, not gigabytes. It's around 36 gigabits. Yeah, including some really unique first-time data and some of the most beautiful images that I think have ever been delivered by a spacecraft. I think so, too. There's really some incredible stuff,

isn't there? I had to look again at that animation of Tavashdar. Could you talk a little bit about that little ornamental fountain you found? Well, it's more than an ornamental fountain. It's a volcano with a muzzle velocity of about a kilometer per second. It's one of the most powerful volcanoes in the solar system going off near Io's North Pole. The Magneto Tail and the fact that it's going to be through June that you'll be collecting data from there?

Well, that's right. We're now about 2,000 Jovian radio down the magneto tail and finding just fascinating stuff, a lot more complexity and some kinds of organization that has got our plasma team just jumping with joy. Did I actually read or did I dream that this tail sort of waves in the wind? Well, it flags in the wind. You can think of it a little bit like a windsock. It's probably a lot more complicated than that. You know, there are idealized models of how these things should work,

but no one's ever been out exploring the depths of a giant planet, Magneto Tail, before. So just like our first trip to Mars and our first trip to Venus and our first trip to the icy Galilean satellites, the list goes on and on, we almost always find that our notions, our ground-based notions and our models, are far outstripped by the richness and reality of nature. Which sure helps make it fun. Talk about some of the other things that this spacecraft discovered as it flew right by Jupiter.

I'm thinking of some of the fine structure you discovered in the rings. I'm thinking of some of the fine structure you discovered in the rings. Yeah, we found interesting clumps of material that may be evidence for recent impacts on the parent bodies in the rings. We know that those clumps can't last very long, so the fact that we've seen them indicates those very recent impacts. When I say recent, I don't mean geologically recent. I mean earlier this year. At least that's the estimate that our ring expert, Mark Showalter at NASA Ames, has given us. Wow. And he's as good as they get. What are some of the other firsts that you're really proud of, or some of the other science,

and images, for that matter, that the spacecraft collected? I'm thinking in particular of one that got a lot of press, and that was the picture of the little red spot, I guess it is. Yeah, we had a lot of that kind of stuff. The thing that I'm actually proudest of, because I'm looking out for the main course, is that the spacecraft and the ground team performed so well that we had an essentially flawless encounter, and that bodes very well for Pluto. In terms of the images, you know, there are some things that will always live in our hearts. The images of the little red spot are quite evocative, aren't they?

Europa rising over Jupiter's limb. Tavash Star really performed. And, of course, because it was up at Io's north pole, it was always in view, never disappearing as Io rotated. And, of course, we got that time sequence of Ashtar, which is very rare. It's rare in planetary science that we see change as a function of time like that. Usually we have a static image. You might compare Mars then to Mars now and see a little difference here or there.

But to actually see a volcano like Io going off in real time just blew people away. I couldn't agree more, and we will provide a link to that and some of these other images on the website, of course. But I had to watch it cycle through at least 10 or 20 times. It's just spectacular. It's mouthwatering, isn't it? And you wish you could just be there. Yeah.

Oh, I'll say. That's always been my goal is to get out to somewhere safely within the magnetic field and look down on that incredible chaos of that planet and its system. You know, I've said to a number of people, and I'll say it to your listening audience, look at that image of Europa rising over Jupiter's land. I'll tell you, I ask people when I give a public talk, I say, have you ever been to Jupiter? Because now you have. Thanks to New Horizons, you really feel like you're an astronaut flying over the limb of Jupiter. And it's something Stanley Kubrick would have loved. Oh, yeah, it really does cry out for some Kubrick treatment with appropriate music. And I saw also that you've got a fan of the mission, I guess, who added some color to it. fan of the mission, I guess, who added some color to it?

Yeah, yeah. More than one, actually, have colored the images using realistic, relatively realistic colors. We don't like to do that. You know, essentially that's PR device. Sometimes it can be scientifically useful, but in this case it was the image was taken as one of our Kodak moments because we knew this artistic geometry would occur. But the colorized version is very evocative, it really is. You know, this is maybe a hallmark of this mission, which may have more public participation than any other mission that I can think of.

I'm thinking of the fact that in this great range of instruments that you've got, you've got one built by students. Oh, we do. It's the first planetary mission ever to have a student-built instrument. And when I suggested that we should do that, it was quite controversial. But it has really won people over, not only the students and the education public outreach community, but I think the public is taken with the fact that we went out on a limb and did this, and it worked. And it's a, what, a dust collection tool?

It's a dust counter. The other thing that we did that was really a forefront, and we wrote it into the proposal in 2001, is we said at Pluto and at Jupiter, we will devote a small fraction of the observations to public request observations. For, you know, artistic or scientific reasons, things contributed by the public where we saw an idea that wasn't something we thought of. And Europa Rising and some of the other Kodak moments that we put out there were born back in 2001 as a result of that forward thinking in our proposal. And we kept to our promise.

And when it came time to plan the Jupiter encounter, we went out to the cognoscente and the public who wanted to make a contribution, and we had some ideas and selected what we thought were the best. And it's really worked out. I hope other missions do that. And, of course, I'd get in trouble if I didn't mention the over 430,000 names, including my own, that are on that CD that you're carrying along. Yeah. A lot of people wanted to get their names hitched to that A-train to the Kuiper Belt, didn't they?

We'll hear more from New Horizons Principal Investigator Alan Stern when Planetary Radio continues. I'm Sally Ride. After becoming the first American woman in space, I dedicated myself to supporting space exploration and the education and inspiration of our youth. That's why I formed Sally Ride Science, and that's why I support the Planetary Society. The Society works with space agencies around the world and gets people directly involved with real space missions. It takes a lot to create exciting projects like the first solar sail,

informative publications like an award-winning magazine, and many other outreach efforts like this radio show. Help make space exploration and inspiration happen. Here's how you can join us. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine.

That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. My guest is Alan Stern, Associate Administrator of, with responsibility for the science mission directorate. So you could say he's his own boss when it comes to the science mission called New Horizons, now leaving Jupiter behind as it heads toward faraway Pluto. Alan is principal investigator for this trip that will take us beyond Pluto, deep into the Kuiper Belt. I know that your top priority is you flew through this relatively dangerous Jovian system

was to make sure that you kept your spacecraft safe and tidy and ready to meet up with Pluto in a few years. Are you pretty happy with the balance that was struck between your ability to gather data and keeping the spacecraft safe? Well, we did keep the spacecraft safe, and we hit the Pluto endpoint. If we hadn't done those two things, we wouldn't have a Pluto mission. Those were our highest priority. We didn't, for example, want the spacecraft to use up too much fuel

or point very sensitive instruments at the sun, those kinds of things. We didn't want to lose contact with the spacecraft. We didn't want to see it go safe hold and lose part of the encounter. Those were our primary objectives, safety and hitting the Pluto endpoint. Second to that was the rehearsal aspect, you know, putting it through the stress test we've talked about. And that worked as well. We had a few observations that failed, but it was only due to the fact that we had some pretty intense radiation, and instruments did what they're supposed to do and saved themselves in that case.

We probably lost 5% of the very closest observations, mostly by the UV spectrometer, Alice. And then we got all this great and wonderful data. It's really beyond my wildest imagination with 700 observations. Now that we know what we're doing, we think we could plan a yet better Jupiter encounter, but we're not going back. Where's that New Horizons 2 when you need it? Really?

Well, who knows? I'll keep my fingers crossed. All right, you already had the fastest human-made object in the universe, and now it's going even faster and headed right for its primary target. Yes and no. I'm going to correct you there. It's a common misconception that we are the fastest spacecraft ever. It's not so.

We're the fastest spacecraft ever to leave the Earth. But, for example, the Voyagers are traveling quite a bit faster than we are because they got four giant planet, in the case of Voyager 2, they got four giant planet boosts. We only get one. Voyager 2 got two. And we could name other spacecraft, some that have come very close to the sun or orbiting very fast.

So we are not the fastest relative to the sun or relative to any given planet, but we were the fastest to leave the Earth. And we are traveling awfully fast by any standard, don't get me wrong. Yeah, what, 52,000 miles or 84,000 kilometers an hour or so? That's right, and we got 9,000 miles per hour out of Jupiter by doing that right. That's half the speed of a space shuttle, just as a bonus. Well, my misconception, if not a popular one, but I do think that a lot of people thought that you were keeping up that record.

Never mind that. You still have a few years out this target, not just one planet, but in a sense two, twin planets. What happens between now and then? Our primary job is twofold. First, to be very good stewards of our spacecraft for eight years so that we're ready and raring to go at Jupiter and are just as healthy as we are today. And there are many aspects to that. And the other is to plan a bang-up Pluto encounter.

And we've made some changes to our concept of how we'll do that. If you want to talk about it, I can tell you. Yeah, I'd like to. In fact, I read that you are about to decide what exact day you'll be arriving at Pluto. That's right. We did a fairly good analysis back in 01 when we wrote the proposal, and we settled on the 14th of July, 2015. The big picture here is after doing Jupiter, I felt very strongly that we should not wait to plan the Pluto encounter. Waiting might be a little better scientifically.

Four years down the road, we know a little more about Pluto, but we would by then have lost the skills that we built up at doing this very successful Jupiter encounter. And many of the people, because of the nature of the budget, would be long gone from the project, the experts who planned the Jupiter encounter. So we asked and received permission to do the encounter planning for Pluto this year in 2008, next year. And then we'll do our first rehearsal in 2009. And I think that the trade is well worth it to have a more reliable Pluto encounter, even if there may be a few things we could have

done better. Better can be the enemy of good enough. That's exactly it. We're already on our way. The first step, the very first baby step in planning the Pluto encounter was to stand back and reassess if we had picked the right day to arrive. We have enough fuel on board to move the arrival date back and forth by a couple weeks either side.

We narrowed that down to about a 20-day period around our nominal closest approach and then put together an enormous table of trades for each date, for every scientific objective, what was better, what was worse, tallied them all up, and we've made our decision preliminarily. And next week at the science team meeting, where all of the New Horizons team will be there, we'll make a final selection on arrival date. And if we were to move off of the 14th of July, then that would necessitate an engine firing, which we would do in October.

But I can tell you already that the 14th of July looks pretty darn good, so we may not move at all. Sounds good to me. The 14th of July looks pretty darn good, so we may not move at all. Sounds good to me. We will be sure to cover that decision on Planetary Radio and perhaps on the Planetary Society website. Not perhaps, for sure. I am amazed that we have made it thus far without any further interruptions. I know that you have to go have dinner with some astronauts, so we better let you go.

I just want to ask you, Washington, it's pretty much identical to Colorado, isn't it? Oh, absolutely. In fact, my view out the window of this office building reminds me of the Flatirons that used to be out my window in Boulder. Thanks for asking. It's pretty different. Thank you, Alan. And thank you so much for spending this time with us. And we will follow the mission and hope to check in with you again.

Well, thanks for your continued interest, and I really appreciate all the Planetary Society did to get us underway back in the difficult years when getting a Pluto mission was controversial, and we intend to deliver, and we're really looking forward to that day. Yeah, well, you certainly are so far, and you are very welcome. Happy it all worked out. Alan Stern is the principal investigator for the New Horizons mission. He's also now the associate administrator of NASA's Science Mission Directorate, formerly director of the Southwest Research Institute Space Science and Engineering Division, which is where Colorado came into the picture.

We'll bring Bruce Betts into the picture in just a minute or two. He'll have a picture of the current night sky after this return visit from Emily. I'm Emily Lakdawalla back with Q&A. How do space navigators know where planetary spacecraft are? Mainly, they use Doppler tracking.

They begin with incredibly precise knowledge of the frequency of their spacecraft's radio transmissions. Since spacecraft travel at high speeds with respect to Earth, the frequency of a radio signal received on Earth is shifted, with the shift in frequency related directly to the speed of the spacecraft. Also, most spacecraft now use their cameras to perform optical navigation, in which they take images of nearby bodies, such as small moons, against a background of stars. Where the moon appears to be in the star field gives useful information to the position of the spacecraft. With these and a few other tricky tracking techniques, navigators can compute the position of spacecraft with incredible accuracy,

to within a few hundred meters of their exact locations. spacecraft with incredible accuracy to within a few hundred meters of their exact locations. That's a few hundred meters of positional precision for spacecraft that can be more than a billion kilometers from Earth. Got a question about the universe? Send it to us at planetaryradio

at planetary.org. And now here's Matt with Bruce Betts, the Director of Projects for the Planetary Society, and he's going to tell us all about the night sky and things like that there. Nice conversation with Alan Stern. Yes, indeed. Excellent. It's very nice of him to continue to make time for us now that he's a major D.C. bureaucratic type. He is indeed.

Good guy. Nice comments about the Planetary Society, too. So what do you have for us? Well, we've got our evening sky, and I think I'll even point out some ways to find stars for those interested, other than looking up. But specific stars, we've got Venus, of course, dominating. Dominating the early evening sky off in the east, looking like the brightest star in the west. Dominatrix. Indeed. And the dominatrix is right near the twins. If you find Venus, which is not that challenging,

then the two bright stars near Venus are Castor and Pollux, twins of Gemini, bright stars. We also have Saturn in the western evening sky, getting closer and closer to Saturn in the sky over the next month. And the moon will make an appearance between the two of them on June 18th. Should be groovy. They'll keep getting closer. Saturn is hanging out near Regulus. Regulus in Leo.

And Leo, one of the constellations I kind of like because it almost looks like a lion. Regulus being kind of the front paw. And Jupiter over in the evening sky, look over the other direction. It is rising in the east, as things will have wanted to do, around sunset and setting in the west around sunrise because it is at opposition on June 6th on the opposite side of the Earth from the sun. And that's our planet roundup. We move on to this week in space history. 1965, Ed White takes the first American space

walk on Gemini 4. Now, as I remember, he just kind of stood up, right? He didn't, did he actually get out of the capsule? I mean, I don't know why I would expect you to know this, but I expect you to know everything. Did he, I thought he just kind of opened the hatch and stood up and looked around. Well, with a Gemini, that's about all you had to do was stand up.

But, no, he made it out. In fact, there were issues with the suit overinflating as they went to vacuum, so there was some challenge getting back in. But he had that cute little handheld rocket thing, a little like holding a TV antenna. It looked like something Wham-O would have made years ago. So I don't believe he went very far away, but he did get out. Good. Okay.

All right, move on to Random Space Fact. Oh, that was masterful. Thank you. Had to make up for last week's. If we could shrink our solar system into the size of a U.S. quarter, the Milky Way galaxy would be the size of? Do you want me to guess? A Buick.

A Buick. No, no. It would be much, much bigger than a Buick. It would be as big as the Earth. Not bad. North America. All right. All right.

Not bad. Not bad. Yeah, yeah. Once again, smallness. Not bad. Not bad. Yeah. Yeah. Once again, smallness, solar system versus just the Milky Way. We only get into the universe. We'll do that some other time. Some Buicks were almost that big.

That's true. That's true. That's my Chevy's, too. On to the trivia contest. Let's start with what we asked you last time. We asked you how many legs does the Phoenix lander have? Phoenix scheduled to launch in early August, headed off to Mars. How'd we do? We got a lot of interesting answers. They were all correct. Nobody said four. Nobody said one.

Kind of cute, wasn't it? A little monopod. And some of them were especially useful and entertaining to us, like good old Torsten out of Germany. Torsten sent us the links to other Martian tripods. You know, we're sending tripods to Mars instead of them to us. And he had pictures from three different generations of War of the Worlds. But the guy who actually did the best research, I think, was John Lees, who actually went to the Jet Propulsion Lab open house a week or so ago. And there was a full-scale model of Phoenix.

And so he actually counted. Brilliant. I think so. But our winner, you probably want to know who actually. I do. I want to know who the actual randomly selected winner is. David Weatherholt. David Weatherholt, who is a previous winner.

He won like last May. So it's been a year, but he hung in there. Do you keep these things in your head just all the time? Well, actually, I check back to see if they've won previously. It's nice to know if it's somebody new because when I send them a note, I say, hey, guess what? You won. Or you won again. That's all I do.

It's very simple. It's our host. But he got it right. Personable. Three legs. He said, I am counting three, said David Weatherholt of Newport News, Virginia. Congratulations, David. We're going to send you a t-shirt.

Congratulations. And if you'd like to try to win a Planetary Radio t-shirt, answer the following. It's time to play that game again, Matt. You know, I need a theme song for this. It's time for, Where in the Solar System? Some more game show or science fiction sounding?

Oh, well, I'll let you work on that. All right. For the moment, we'll just give the question, which is, where in the solar system are the craters Don Quixote and Dulcinea? Oh, is there a Sancho Panza? I don't believe so, no. Okay, all right. At least not on the same body.

So Don Quixote and Dulcinea. Yes. Where are they in the solar system? What body are they on? Okay. All right. Go to planetary.org slash radio to find out how to enter. And you've got until June 4, Monday, June 4 at 2 p.m. to get us your answer.

We're done. All right, everybody. Go out there. Look up the night sky and think about parachutes floating down. Thank you, and good night. That's Bruce Betts. He's the director of projects for the Planetary Society, and he joins us every week here for What's Up?

Nothing funny about that. Now he laughs. Remember, next week we'll take you to the recent Lunar Regolith Challenge in Central California, where robots tried to move enough simulated moon soil to win a quarter of a million dollars for their builders. Can you dig it? Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week, everyone. Thank you.